You can read more here.
From the website:
Atheism [/aythi-iz’m/] is defined as “the belief that God doesn’t exist”.
But atheism is much more than that. It’s about making sense of the world, thinking freely, and feeling liberated from unnecessary guilt and fear. It’s about using your intellect and sense of reason to see through the inconsistencies and intolerance of religion, and having the courage to think for yourself. It’s about relying on evidence rather than giving into irrational insistence, and being brave enough to speak the truth.